Elastic-fluid turbine.



0. D. H. BENTLEY.

ELASTIC FLUID TURBINE.

APPLICATION FILED MAY 5,1913.

Patented Jan 22, 1918.,

nrrnn earns nr i rn OLIVERD. H. BENTLEY, OF BOSTON, MASSACHUSETTS,ASSIGNOR TO B. F. STUBTEVANT COMPANY, OF BOSTON, MASSACHUSETTS, ACORPORATION OF MASSACHUSETTS.

ELASTIC-FLUID TURBINE.

Specification of Letters Patent.

Patented Jan. 22, 191%..

To all whom it may concern:

Be it known that I, OLIVER D. H. Binar- LEY, a citizen of the UnitedStates, reslding at Hyde Park, Boston, in the county oi Sutiolk andState of Massachusetts, have invented certain new and usefulImprovements in Elastic-Fluid Turbines; and I do hereby declare thefollowing to be a full, clear, and exact description of the lnvention,such as will enable others skilled in the art to which it appertains tomake and use the same.

The present invention relates to elastlc fluid turbines, and moreparticularly to the type of elastic fiuid turbine in which the elasticfluid is delivered at high veloclty from an expanding nozzle intosubstantially semi-cylindrical rotor buckets, from which it isdischarged into substantially semi-cylindrical stator buckets whichredirect the steam into the same set of rotor buckets. The object of thepresent invention is to reorganize and improve the construction andarrangement of the buckets and the expanding nozzle so as to secure abetter and more efiicient flow of the elastic fluid through the buckets.The present invention in its narrower aspects is intended moreparticularly as. an improvement upon the stat onary reversing bucketsdisclosed in my prior Patent 1,042,871, dated October 29, 1912.

l/Vith the above object in view, the present invention consists in theimprovement in elastic fluid turbines hereinafter described andparticularly pointed out in the claims.

In the accompanying drawings which illustrate the preferred embodimentof the present invention, Figure 1 is a view of the block or segment inWhich are formed the stationary or stator buckets and the expandingnozzle, looking into the open mouths of the buckets; Fig. 2 is a sectiontaken along the line 22 of Fig. 1, the section being carried down intothe rotor or bucket wheel; and Fig. 3 is a section taken on a planethrough the steam guiding rib of one of the stator buckets. The plane ofthe section of Fig. 3 passes through the middle of the inclined statorbuckets parallel with the flat end walls thereof and is inclined to theplane of the paper in both Figs. 1 and 2, the line of intersection ofthis plane and the plane of the paper being indicated by the line 33 inFigs. 1 and 2.

Referring to the drawings, 2 indicates a fragment of the rotor or bucketWheel, which is preferably formed of a single steel forging, in theperiphery of Which are milled semi-cylindrical or U-shaped reversingbuckets 1. The fiat end walls of these semi-cylindrical buckets aresubstantially parallel and are inclined to the intersecting radii of therotor, but are parallel to the axis of the rotor. The partitions 6between the rotor buckets are beveled at their edges to offer a minimumresistance to the intlowing steam.

The steam is delivered at high velocity into the receiving sides of therotor buckets by means of an expanding nozzle 10. Forward of the nozzle10, in the direction of rotation of the rotor wheel, are four U- shapedor substantially semi-cylindrical stator reversing buckets 12, 14, 16and 18. The mouths of these buckets are inclined to the direction ofmovement of the periphery of the rotor wheel, the flat end walls of thebuckets being substantially parallel with each other and inclined tointersecting radii of the rotor wheel, and also inclined to the axis ofthe rotor. Back of the nozzle 10, relatively to the direction ofrotation of the rotor Wheel, is a supplemental U-shaped or substantiallysemi-cylindrical stator reversing bucket 20. The mouth of this bucket isnot inclined like the other stator buckets, the substantially parallelflat end Walls being parallel to the axis of the rotor and inclined tothe intersecting radii of the rotor. The stator buckets and theexpanding nozzle are formed in a one-piece metal block known as a nozzleand bucket seg ment, and are arranged substantially as in myabove-mentioned prior patent. The nartitions between the adjacentbuckets of both the rotor and the stator are substantially parallel witheach other (allowing for the curvature of the rotor), and extend fromthe bottoms of the buckets flush with the mouths of the buckets. Thesubstantially semi-circular curved peripheral walls 22 of the stator androtor buckets are all provided with steam guiding ribs or projections24:, as best shown in Fig. 2, the rib 24 of each bucket serving todivide the peripheral wall into a plurality of round-bottomed grooves.The rib serves to guide the steam flowing along the wall 22 in a pathlying in a con stant plane and to maintain a uniform distribution ofsteam-flow along the curved Wall of the bucket. Thus the mixing of steamcurrents is reduced, and eddies and interferences are minimized. At themouths of the buckets the junctions between the end walls and theperipheral walls 22 are squared, as shown in Fig. l, and the steamguiding ribs near the mouths of the buckets fade away or merge with thewalls 22. Tlns is especially important at the receiving sides 26 of thebuckets, as it removes all impediment to the free iniiow of steam. It isalso important that the ribs 24 should not extend tothe mouths of thebuckets at the discharge sides 28, in order that the steam may bedischarged at the extreme edges of the buckets in position to enter thereceiving sldes ol the opposing buckets at their extreme edges.

This form of bucket may be easily cut with a milling cutter appliedtwice at each bucket. faces and its edge is semi-circular in crosssection so that the peripheral wall of the chamber is divided by the rib2a, which is left between the two grooves cut by the two applications ofthe milling cutter. After thebuckets are milled, the mouths are finishedby squaring the corners of the mouths and tapering olf the ends of theribs 24. This type of bucket is particularly adapted for the inclinedbuckets of the stator. As illustrated in the drawings, the statorbuckets 12, 14, 16 and 18 are inclined so that they have substantiallyrhomboidal mouths. This form of bucket cannot be aproximated with asingle application of a roughed out cutter, but can be milled with twoapplica- V tions of a milling cutter, as above described.

Another feature of the invention resides in the form of the nozzlemouth, which is trapezoidal, asillustrated in ig. 1, so as to adapt itto the most economical use of the space between the supplemental statorbucket 20 and the inclined stator bucket 1 Thetwo stator buckets20 and12 have their receiving sides 26 in proximity to each other, and theirdischarge sides 28 located forward and back of the nozzle 10, leaving atriangle within which the nozzle must be placed. The trapezoidal form ofthe nozzle mouth, therefore, for a given mouth area, permits the steamto be delivered nearer the edges of the receiving sides of the rotorbuckets and so insures the more eliicient application of the-steam jetto the rotor. It is to be recognized that the partition walls betweenthe stator buckets and the nozzle openlng should be thin, to the endthat the stator buckets and nozzle should deliver a sub stantiallycontinuous stream of steam into the. rotor buckets. The trapezoidal formof nozzle permits the sides of the nozzle mouth to beparallel with andclose to the sidesof the adjacent bucket mouths, so that the steamcoming from the nozzle merges with the reversed steam coming from thedis- The milling cutter has flat end charge sides of the bucketsandforms with it a continuous stream of steam ssumg from the discharge.ed 'e of the nozzle andbucket segment,"the thin partition Walls formingpractically no gap or break in the cross section of the stream. 7

While the preferred embodiment of the present invention has beenspecifically illustrated and described, it is to be understood. that theinvention is not limited to its preferred embodimenlabut may be embodiedin other constructions of elastic fluid turbines within the scope of theinvention as set forth in the following claims 1. Anelastic fluidturbine havinga circularly extending series of deflecting-surfaces,transversely arranged 'with respect to the plane of rotation of theturbine, the adjacent surfaces being substantially parallel and, offsetone from another, each of said surfaces being divided'into a pluralityof parallel channels with intermediateribs extending above the bottomsof the chaneach of which surfaces is divided into a plurality ofparallel channelswith comparatively shallow intermediate ribs orseptaextending above the bottoms of the channels on each side; andcomparatively deep septa separating the. adjacent deflectingsurfaces. Ir g 3. An. elastic fluid turbine having,in ;con1 bination, a rotorhaving reversing buckets, and a stator comprising an expanding nez- 1zle having a trapezoidal mouth for delivery ing the elastic fluid athigh velocity tothe rotor buckets, and two reversing bucketsfonreceiving the fiuidfrom the rotorbucketsandredirecting itto the same setof rotor buckets having their receiving sides in proximity to each otherand'their. discharge sides separated from eachother and located forwardand back of the nozzle, substantially as described. 1

4. An elastic fluid turbine having, in combination, a rotor havingreversingbuckets, and a stator-comprising an inclinedlreversing bucketreceiving the fluid from therotor buckets and redirecting it to the sameset of rotor'buckets and an expanding nozzle having a trapezoidal mouthfor delivering the elastic fluidathigh velocity to the rotor, the .mouthof said nozzle-having. onset itssides substantially parallel to themouth of 1 the inclined stator bucket and in proximity to. the dischargeside of. said'bucket',-Isuba stantially as described. a r

5. An elastic fluid turbine having a sub stantially U-shaped bucket ofwhich the 30- i curved deflecting-surface extends, in crosssection, in ageneral direction normal to the plane or" flow of the motive-fluid, butis provided with a longitudinally-extending rib which divides the bottomof the bucket into two substantially parallel channels, the ribprojecting above the bottoms of the channels on each side thereof.

6. A substantially U-shaped bucket for an elastic fluid turbine havingits curved wall provided for the greater part of its length with a steamguiding rib or projection and round-bottomed grooves upon each side ofand parallel with the rib or projection, substantially as described.

7. A substantially U-shaped bucket for an elastic fluid turbine havingits curved wall for the greater part of its length cardioidally cuspedin transverse section, substantially as described.

8. A bucket for an elastic fluid turbine having Hat and substantiallyparallel end walls extending to the mouth of the bucket and having asubstantially semi-circular peripheral wall provided with a steamguiding rib or projection, substantially as described.

9. An elastic fluid turbine having, in combination, a plurality oiadjacent substantially U-shaped buckets separated by substantially fiatand substantially parallel partition walls which extend to the mouths ofthe buckets, the curved walls of the buckets being provided with steamguiding ribs or projections, substantially as described.

10. An elastic fluid turbine having, in combination, a plurality ofadjacent substantially U-shaped reversing buckets separated bysubstantially fiat and substantially parallel partitions extending tothe mouths of the buckets, the curved peripheral walls of the bucketsbeing provided with steam guiding ribs or projections, the mouths ofsaid buckets being squared, and the steam guiding ribs or projectionsbeing tapered near the mouths of the buckets on the receiving sides ofthe buckets to gradually merge with the squared mouths of the buckets,substantially as described.

11. A substantially U-shaped bucket for an elastic fluid turbineprovided with a steam guiding rib or projection on its curved peripheralwall, said steam guiding rib or projection being tapered to graduallymerge with the wall. near the mouth of the bucket, substantially asdescribed.

12. An elastic fluid turbine having a substantially U-shaped bucket ofwhich the curved deflecting-surface is divided, at the bottom of thebucket, into a plurality of substantially parallel shallow channels, thebottoms of the channels being, in cross section, in alinementsubstantially at right angles to the end walls of the bucket.

13. An elastic fluid turbine having a substantially U-shaped bucket ofwhich the curved deflecting-surface is divided, at the bottom of thebucket, into a plurality of substantially parallel channels ofcurvilinear cross-section transversely arranged with respect to theplane of rotation of the turbine.

OLIVER D. H. BENTLEY. Witnesses:

H. A. MCKENNA, L. I. Smrrr.

Uopiea or this patent may be obtained for five cents each, by addressingthe Commissioner of Eatenta, Washington, D. U.

It is hereby certified that in Letters Patent No. 1,254,465, grantedJanuary 22,

1918 upon the application of Oliver D. H. Bentley, of Boston,Massachusetts, for

an improvement in Elastic-Fluid Turbines, an error appears in theprinted specification requiring correction as follows: Page 2, strikeout lines 35-36 and insert the Words and syllables with a singleapplication of a milling cutter, but can be roughed out with twoapplicar; and that the said Letters Patent should be read with thiscorrection therein that the same may conform to the record of the casein the Patent Ofiic'e.

Signed and sealed this 26th day of February, A. 1)., 1918.

[SEAL] F. W. H. CLAY,

Acting Uommss-ioner of Patents.

